At center, Metta World Peace, formerly Ron Artest, of the Los Angeles Lakers is ejected for elbowing James Harden of the Oklahoma City Thunder at Staples Center on April 22, 2012 in Los Angeles, California.

If you’re going to name yourself Metta World Peace, you can’t betray your name with your elbows.

That’s exactly what World Peace, the former Ron Artest, did on Sunday afternoon. After finishing a fast break dunk, the Los Angeles Lakers’ World Peace pounded his chest in celebration while running back down court. Oklahoma City Thunder’s James Harden, trailing the play, made contact with World Peace: the Laker forward finished his flourish with a nasty, borderline disgusting elbow to Harden’s head. See the video below. Fair warning: the clip is not easy to watch.

After the elbow, Harden lay still on the court for a scary few minutes. According to Darnell Mayberry of The Oklahoman, Harden, who did not return to the game, was diagnosed with a concussion. Under the NBA’s new protocols, an independent neurologist must examine Harden before he is cleared to play. The Thunder have two regular season games left, and even though Oklahoma City lost to the Lakers in double overtime on Sunday 114-106, the team is still in contention for a top-seed, and home-court advantage, throughout the Western Conference playoffs.

World Peace claimed that the attack was an accident. “I got real emotional and excited, and it was unfortunate that James had to get hit with the unintentional elbow,” he said. “I hope he’s OK. Oklahoma, they’re playing for a championship this year. I apologize to the Thunder and James Harden. It was just unfortunate.”

We don’t believe this explanation. Players often pound their chests after a nice play. But they don’t wind up their shoulder, and throw an “air elbow” where the head of an opposing player might happen to be. The incident is even more unfortunate since Artest – and like the ABC halftime studio announcers at Sunday’s game, we’re going to ditch the World Peace facade after that attack on Harden – had come so far since his 86-game suspension in 2004-2005 for his role in the infamous “Malace at the Palace” brawl between the Indiana Pacers and Detroit Pistons. He even won the NBA’s good citizenship award last season.

Artest’s actions against Harden aren’t as shocking as they were that night in Detroit, when he went into the stands to fight fans. But I’m not convinced that the NBA should take the elbow much more lightly. If you can stomach it, watch Artest’s move in slow motion a few times. Artest is 6’7″, 260 pounds: Harden is lucky that the force of the blow did not inflict more serious damage. But as we’ve come to know over the last few years, any type of concussion is plenty serious.

The Thunder is one of the NBA’s best stories, a small market-team that has become a title contender through smart management and unselfish play (and the emergence of Kevin Durant and Russell Westbrook as superstars). Harden is one of the NBA’s rising talents. If Harden has to miss playoff games, or returns to the court a shell of his former self – these are real threats following a head injury – and Artest’s elbow impacts the finish of Oklahoma City’s season, the entire 2011-2012 NBA campaign becomes compromised. After the protracted preseason lockout, a compelling regular season helped erase most fan ill-will. With one swing of his massive left elbow, Artest may have marred all that.